Huxley's Sliding Filament Theory: how muscles contract

The sliding filament theory by Andrew Huxley was first postulated around the early 1950's to describe how muscles contract. This will be a very brief introduction to muscle contractions and what happens when muscle fibers are innervated.

Sliding Filament Theory
It all starts with an action potential that signals the muscle to fire coming from the brain. The action potential signals the release of acetylcholine (a neurotransmitter) to be released at the synaptic cleft along with calcium ions opening up the channel of neurotransmitters to stimulate muscle contraction.

The synaptic cleft is the terminal region where a neuron meets a muscle fiber. From there, calcium ions attach to actin causing what is called cross bridging between actin and myosin. ATP is the compound that powers this cross bridging to happen. From there, actin and myosin overlap eachother causing the muscle to contract.

The sarcomere which is the unit that contains the actin and myosin filaments shortens. There is much more details that go into the science behind muscle contractions. Wanted to give you guys a very brief and quick introduction to the science of muscle contractions which is also known as Huxley's Sliding Filament Theory which was found by Andrew Huxley a biophysicist who won a Nobel Peace prize in 1963.

Coach Cano